Production of isoprene.



ITED STATES PATENT on KARL STEPHAN, F CHARLOTTENBURG, GERMANY, ASSIGNOR T0 CIHEMISCHE FABRIK LA'U'F ACTIEN (VORM. E. SCHERING), OF BERLIN, GERMANY.

PRODUCTION Oil ISOPRENE.

1,057,680. No Drawing.

' Specification of Letters Patent.

Patented Apr. 1, 1913.

Application filed January 24, 1912. Serial No. 673,096.

To all whom it may concern Be it known that I, KARL STEPHAN, doctor of philosophy, chemist, citizen of the German Empire, residing at Charlottenv the great difference in the behavior of the various terpene hydrocarbons it was by no means 'to be expected that it would be possible to obtain isoprene from nopinene.

E baamples. v

1. Nopinene is caused to pass through an iron tube heated to from about 500 to 520 centigrade and connected to a cooled condenser. In addition to other products having a higher boiling point, isoprene collects, thls can easily be obtained in a pure condition by fractional distillation. The amount .of isoprene obtained the boiling point of which lies between 32 and 40, is about one tenth of the weight of the nopinene.

2. Nopinene in the form of vapor is caused to passslowly over electrically heated wire gauze. The vapors are condensed and the resulting products are treated as in the first example. The amount of isoprene obtained is about one fifth of the weight oi the nopinene.

I claim as my invention 1. The, process of producing isoprene which consists in heating nopinene to a temperature which is sufficiently higher than the boiling point of nopinene to cause the decomposition of the latter substance into isoprene and other compounds, condensing the vapors and isolating-dire";isoprene so formed.

2. The process of producing isoprene which consists in heating noplnene to a temperature "of about 500 centigrade, condensing the vapors and isolating the. isoprene so forme v 3. The process of 'pr'o'ducing isoprene which conslsts in passing nopinene in contact with metal heated" to a temperaturewhich raises the temperature of the nopinene to about 500 centigrade, condensing the vapors, and isolating the isoprene by fractional distillation.

In testimony whereof I have hereunto set my signature in the. presence of two subscribing witnesses.

KARL STEPHAN. Witnesses-z WOLDEMAR HAUPT, HENRY HASPER. 

